In recent years, it has become known that the propagation characteristics of electromagnetic waves are able to be controlled by periodically arranging conductor patterns having a specific structure (hereinafter, called a metamaterial). For example, a reduction in size and thickness of an antenna can be achieved by using a metamaterial.
There area so-called right-handed system, left-handed system, and right-handed and left-handed composite system in a metamaterial. Among them, when a metamaterial of a right-handed and left-handed composite system is used as an antenna, increasing the bandwidth of zero-order resonance is preferable because the band of an antenna is widened. In order to increase the bandwidth of zero-order resonance, it is preferable to create a design so as to satisfy so-called “balance conditions” to match the resonance frequency of a series circuit to the resonance frequency of a shunt circuit.
Incidentally, Patent Document 1 discloses a technique in which a plurality of metal platelets are electrically connected to each other through a capacitance element, specifically, a chip capacitance, in order to lower the operating frequency band of the electromagnetic band gap (EBG), which is an example of a metamaterial.